rear air brake leaks on new M1078

[auctionaddict]

I just listed some for sale in the classifieds ...

 

[Blackmagic94]

Looked at it again last night as compared to my mtv on the air spring assemblies the mtv has plastic blue covers on the inboard side while the lmtv does not

 

[10Lugger]

Also if the CTIS box is flashing all modes, what TM should I use to address this issue, does anyone sell a kit with all the seals to make these work again?

Fix your current leak first then see if that does not take care of your CTIS all flash

 

[Blackmagic94]

[SUB]yu[/SUB]The leak is coming from that purge valve only.


I also inspected the spring pucks and noticed the adjustments. Could this be an issue. The tow truck driver had messed with them to unload.

 

[NDT]

Help us with your nomenclature use. The "spring puck" is called the brake chamber. Your wrecker driver had the brakes "caged" which is to use a stud/nut assy to compress the spring inside the brake chamber to allow the truck to roll. There is no adjustment inside the chamber. Your wrecker driver or someone lost the blue triangular plugs.

Are you now saying your leak is coming from the purge valve and not the inversion valve?

 

[Blackmagic94]

Whatever the previous mentioned valve was is where the leak is

 

[doghead]

Someone needs to open the TMs, and learn what they are talking about, learn nomenclature and look at the pictures(in the parts tm) to correctly identify what he is talking about.

 

[doghead]

With no understanding of air brakes, you should not be working on or driving this truck.

Please educate yourself before you hurt yourself or someone else.

 

[SSG Gibb]

Find yourself an ECS/AMSA/ Or AGR Mechanic and become Good friend with them as your in for all kinds of "Interesting" issues with your new found addiction. But I will tell you that when dealing with Any vehicle that Has CTIS or air brake issues a spray bottle of soapy water is a great tool.

 

[Blackmagic94]

Yes I am going to do the soapy water test as the mark 1 ears didnt hear anything from other spots and as for our resident mod, I am not driving the vehicle until it is corrected but please dont imply that I am not capaable of working on the vehicle. Thank you for the concerns though.

 

[SSG Gibb]

Please don't misunderstand my meaning when i say make friends with someone who works on these trucks for a living. I am one of those guys. It's alot easier to diagnose a truck when I'm standing right in front of it and thus time/money saving. Best of luck no inferences intended.

 

[Blackmagic94]

update on rear brakes issue and help needed

My mobile mechanic called and said he inspected the M1078 for the inversion valve purging excessive air as some may recall


He said he narrowed the issue down to a module with an air house that is above the diff but in front of it that has a spring loaded arm going down to the diff, he said if he disconnect that it would stop the leak and the brakes worked 100% at that point but once he reconnected it would purge from the inversion valve with the brakes applied.



I am out of town so does anyone have an idea what thing spring loaded arm thing is and what is its purpose so I can relay the info to him.

 

[PowerstrokeNC]

I have seen this switch but didn't pay much attention to it yet, keep us informed of your progress, I am out of town too so can't take a look either. thanks

 

[PowerstrokeNC]

pic didn't post hang on...

 

[PowerstrokeNC]

Appears to be a load sensing valve...

 

[PowerstrokeNC]

 

[PowerstrokeNC]

The foot control valve is operated by the brake pedal (5) and receives pressurized air from both the primary and
secondary air tanks. The foot control valve is a dual activation design, with one set of ports supplying air to the front
brakes from the secondary air tank and another set of ports supplying air to the rear brakes from the primary air tank.
The plumbing between the primary and secondary air tanks is designed to allow controlled braking in the event of a
failure in either the primary (rear brakes) or secondary (front brakes) brake circuit. Air from the foot control valve is
supplied to the load sensing valve (6) which, in turn, controls air delivery to the relay valve (7). The load sensing valve
is mounted on a crossmember and connected, by a spring and cable, to the rear axle. The arrangement of the load
sensing valve provides a mechanical anti-lock feature to the rear brakes by sending less air to the rear brakes when
the vehicle is not heavily loaded. The relay valve is used to provide the Operator with quicker brake response. An
inversion valve redirects air from the secondary brake circuit to the primary brake circuit in case of loss of pressure
in the primary brake circuit. This feature allows control of the spring brakes and prevents early rear brake lock-up.

 

[Blackmagic94]

That is the valve thanks,



so it basically changing brake bias based on load, doesn't sound like the end of the world to bypass this feature or not?

Knowing BAE its probably a 2500 dollar part lol

 

[PowerstrokeNC]

Well you open a lot of variables, if the truck is loaded you prob would want more brake force on the back. However if you never put weight in it, would it matter.... prob not... I bet you could find a new/used one without too much trouble.

 

[doghead]

Merged with original thread.

Next time continue your thread(do not start a second thread).